The following relates generally to wireless communication, and more specifically to channel state information estimation using phase noise and channel information reporting.
Wireless communications systems are widely deployed to provide various types of communication content such as voice, video, packet data, messaging, broadcast, and so on. These systems may be capable of supporting communication with multiple users by sharing the available system resources (e.g., time, frequency, and power). Examples of such multiple-access systems include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, and orthogonal frequency division multiple access (OFDMA) systems. A wireless multiple-access communications system may include a number of base stations, each simultaneously supporting communication for multiple communication devices, which may each be referred to as a user equipment (UE).
Wireless communications system may use various reference signals to determine channel information, e.g., channel measurement and feedback reporting. For example, channel state information reference signals (CSI-RS) allows a UE to estimate narrowband channel performance for different antenna ports at the transmitting base stations. Some wireless communications may operate in the millimeter wave (mmW) spectrum that may utilize beamforming to increase the strength of wireless signals. In some cases, mmW transceivers may experience higher phase noise levels than non-mmW transceivers, e.g., transceivers configured for communications in the sub-6 GHz spectrum. The increased phase noise may be based on a higher frequency ratio between a local oscillator and a temperature compensated crystal oscillator of the transceiver, noisier voltage controlled oscillators, etc. In some examples, the UE (e.g., the receiver in downlink communications) may generate a large portion of the phase noise in the received signals, e.g., the oscillator components in the UE transceiver may have higher tolerance levels, may be manufactured using less expensive components, etc. In some scenarios, the phase noise may cause variations in phase of received signals within the duration of a single symbol.
Some wireless communications systems may operate in the millimeter wave (mmW) spectrum and may utilize beamforming to increase the strength of wireless signals. In some cases, mmW transceivers may experience higher phase noise levels than non-mmW transceivers (e.g., transceivers configured for communications in the sub-6 GHz spectrum). The increased phase noise may be based on a higher frequency ratio between a local oscillator and a temperature compensated crystal oscillator of the transceiver, noisier voltage controlled oscillators, etc. In some examples, the UE (e.g., the receiver in downlink communications) may generate a large portion of the phase noise in the received signals (e.g., the oscillator components in the UE transceiver may have higher tolerance levels, may be manufactured using less expensive components, etc.). In some cases, the phase noise may cause variations in phase of received signals within the duration of a single symbol. Phase noise variation may lead to signal reception errors, and may degrade system performance.